It's not a bug. Events aren't meant to be triggered by scripts/commands. If you want to do something when you use /close, well, just put the necessary commands right after /close. In case you want to monitor users typing /close or something, you could use on INPUT. I know, this is far from perfect, but having /close trigger an event is not the way to go: imo it is very important that commands cannot trigger events (except signals), I hope it stays this way.